A linear barcode is a one-dimensional pattern of bars and spaces that encodes numbers or text so scanners, imagers, and camera apps can read it quickly and cheaply. Unlike two-dimensional symbols such as QR codes, classic barcodes spread information along a single axis, which makes them ideal for product labels, shelf tags, shipping cartons, library stickers, asset tags, and point-of-sale workflows where hardware has decades of tuning for black bars on a light background. SynthQuery’s Barcode Generator is a free, browser-based maker for the nine most common retail and logistics symbologies you will encounter in small business and mid-market operations: Code 128 for dense alphanumeric strings, Code 39 for legacy uppercase systems, EAN-13 and EAN-8 for consumer GTIN contexts, UPC-A and UPC-E for North American packaging variants, ITF-14 for case-level fourteen-digit codes, Codabar for institutional numbering with simple start and stop patterns, and MSI for purely numeric internal tickets. You type or paste data, pick a format, and the page validates lengths and check digits before drawing anything, so you catch data entry mistakes before they reach a printer. Customization covers the practical print variables teams argue about in prepress: module width, bar height, bar and background colors, optional human-readable text under the symbol, and caption font size when digits should remain legible at small sizes. A live SVG preview updates as you adjust settings, which helps you judge quiet zones and contrast without exporting blind. When you are ready, download PNG or JPG raster files with DPI-oriented scaling relative to the common ninety-six CSS pixel baseline, or grab SVG for lossless placement in Illustrator, Affinity, Figma, or InDesign. Batch mode accepts a list of values—one per line, up to one hundred rows per session—so you can paste a column from a spreadsheet or a simple text export, review per-row validation, preview any row, download individual files, or bundle every valid row into a single ZIP archive in your choice of PNG, JPG, or SVG. Encoding runs locally with the MIT-licensed JsBarcode library after it loads; SynthQuery servers do not receive your barcode payloads for the workflow described here. When you also need AI-assisted writing checks, continue to the core AI Detector and Humanizer; when you need square QR codes for marketing links, use the QR tool linked below; when you need Pharmacode specifically, use Photo Barcode Gen on SynthQuery, which extends this symbology set with that niche encoder.

The interface is organized into Single and Batch tabs so you can either craft one perfect symbol or work through a short list without repeating clicks. The symbology selector lists nine formats with concise hints about character sets and digit lengths. Retail GTIN family inputs strip accidental spaces, compare your check digit against the same weighting the encoder applies, and surface plain-language errors when parity fails. Code 39 screens for disallowed characters; MSI insists on numeric-only payloads; Codabar tolerates optional guard letters while explaining how start and stop symbols behave. The preview panel renders a live SVG with an accessible description and polite status announcements for assistive technology users. Sliders adjust bar module width between one and six pixels in renderer units, bar height between twenty-four and one hundred sixty pixels, and caption font size between eight and twenty-eight pixels whenever human-readable text is visible. A switch hides caption text entirely when your layout prints digits separately or when the graphic must stay minimal. Color pickers pair with validated hexadecimal fields so you cannot accidentally lock the UI into an unparseable token; high contrast remains the default because low-contrast barcodes fail in warehouses and under supermarket LEDs. Single-mode downloads expose PNG, JPG, and SVG. Raster exports multiply the SVG layout box by your chosen DPI preset divided by ninety-six, approximating how designers reason about print resolution after working in screen pixels. JPEG export composites a white matte under the bars to avoid dark compression artifacts around edges. Batch mode adds a scrollable table with row numbers, truncated values for scanning, validation status, and per-row PNG, JPG, and SVG buttons. A ZIP builder walks only validated rows, names files with zero-padded indices to preserve order, and respects the same styling options as the preview so bulk output matches your single-symbol tuning. Invalid rows are skipped automatically with an on-screen count so you know how many symbols the archive contains.

Code 128 encodes full ASCII by switching among code sets, producing shorter bars than Code 39 for the same payload. Code 39 restricts characters but remains common in legacy industrial readers. EAN-13 carries twelve data digits plus a modulo-ten check digit computed with alternating one-and-three weights from the left; the leading digit influences parity patterns on the left half. EAN-8 applies a similar checksum across seven body digits. UPC-A uses eleven data digits plus check with a different odd-even weighting than EAN-13; UPC-E compresses certain zero patterns when manufacturer rules allow. ITF-14 is an Interleaved 2 of 5 derivative padded to fourteen digits with a checksum over the first thirteen. Codabar wraps content between start and stop symbols; many workflows let the encoder add default guards when you supply only the body. MSI represents decimal digits in binary-like bar patterns; some ecosystems add secondary check digits in other software, but this page exposes the base encoder mirrored in JsBarcode. Raster scaling multiplies the SVG bounding box by DPI over ninety-six, giving a practical proxy for print workflows without pretending to know your physical label width. Scanners ultimately care about module width in millimeters, contrast, focus, and quiet zones. SVG avoids pixel grids and remains the archival format when downstream tools resize. JPEG compression can soften edges if quality is too low; prefer PNG or SVG when modules are tiny.

Product teams export SVG barcodes into packaging mockups while waiting for official GTIN assignment from GS1, swapping placeholder digits that still satisfy checksum rules so scanners respond realistically in usability tests. Inventory coordinators paste location codes from a WMS CSV into batch mode, ZIP the PNG set, and attach the archive to an internal wiki page illustrating rack labeling standards. Retail merchandisers print EAN-13 symbols on temporary shelf talkers for seasonal promotions, tuning bar height until handheld imagers read reliably under new LED retrofits. Shipping desks generate ITF-14 case codes for photography before corrugated plates arrive from the flexographic vendor, keeping marketing shots aligned with logistics documentation. Library volunteers rebuild Codabar asset tags for tool lending programs. Event producers turn registration dumps into MSI-encoded thermal tickets when the vendor exports only plain text. Asset-tracking startups embed UPC-E on jewelry hang tags where vertical space is scarce. SaaS documentation teams drop PNG examples next to API tables so integrators recognize valid payload lengths. QA engineers regression-test decoders with edge-case values generated here. Educators export JPEG slides that show both bars and digits when teaching weighted checksum algorithms. After generating artwork, teams often pair this utility with SynthQuery’s QR Code for Photographers for omnichannel campaigns, Product Schema Generator when structured data must reference GTIN fields, and COGS Calculator spreadsheets when inventory discussions follow labeling projects.

Use this sequence whenever you need scannable linear barcodes without opening a full label MIS.

This generator does not register GTINs with GS1, does not issue company prefixes, and does not replace ISO/IEC verifier hardware. Confirm symbology rules with retailers and 3PL partners before mass production. Batch mode caps at one hundred non-empty lines to protect lower-powered devices; merge millions of labels from your ERP instead. Pharmacode is intentionally omitted here—use Photo Barcode Gen when that symbology is required. Maintain adequate quiet zones around symbols; tight cropping is a common cause of no-reads. Store SVG when possible and derive PNG or JPEG per channel to avoid generational loss.